1. Field of the Invention
The present invention relates generally to the field of therapeutic rehabilitation devices and, more particularly, to devices facilitating exercise and rehabilitation of the ankle.
2. Description of the Prior Art
The ankle joint is capable of a wide range of motion. Such motion includes plantar flexion (moving the foot so that the toes go down), inversion (moving the bottom of the foot towards the midline of the body), eversion (moving the bottom of the foot away from the midline of the body), and rotation of the foot about a longitudinal or vertical axis. Because the ankle joint supports the entire weight of the body during upright movement it is at time subjected to severe stresses which can cause injury, especially during athletic type activities. Due to such circumstances, ankle joint injuries are among the most common injuries suffered by athletes.
As a consequence of an injury to the ankle joint, such as a sprain, strain or break, the soft tissues which encompass the joint, including muscles, ligaments, tendons and nerves, are often immobilized for a period of time and become weakened or atrophied. Thus, after the swelling and pair associated with the injury have diminished, it is important to rehabilitate the ankle to restore stability, range of movement, increase strength and recover neurological capacities necessary to its normal functioning. One way this is accomplished is by exercising the ankle through a desired range of movements on a device which is capable of providing a gradually increasing resistance to such movements.
Previous known devices designed for ankle rehabilitation may be characterized by the different tensioning structures used to oppose movement. Some devices provide movement in only one direction or in a very limited number of directions. Other devices lack a variable tensioning capability throughout the full range of motion. Yet others are difficult to adjust the direction of the resistance force and/or the level of resistance with the device attached to the user's foot. Also, many devices utilize weight plates or cylinders which only provide concentric resistance and not isometric or eccentric muscle contraction resistance. In addition, many devices are too bulky to offer easy user portability or are not adjustably sizable to accommodate a wide range of foot and ankle sizes.